This way you can specify as previously set the dhcp parameter via global.dhcp.xxx
and get the result via global.dhcp.xxx
This is need for the defaultenv-2 to add the bootp suppport.
Use it on defaultenv too to have only one set of var.
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>